#!/bin/sh
#
# This scripts adds local version information from the version
# control systems git, mercurial (hg) and subversion (svn).
#
# If something goes wrong, send a mail the kernel build mailinglist
# (see MAINTAINERS) and CC Nico Schottelius
# <nico-linuxsetlocalversion -at- schottelius.org>.
#
#

#
# Use the following line in your configure.ac, so that $(VERSION) will
# automatically be up-to-date each time configure is run (and note that
# since configure.ac no longer includes a version string, Makefile rules
# should not depend on configure.ac for version updates).
#
# AC_INIT([GNU project],
#         m4_esyscmd([build-aux/git-version-gen .tarball-version]),
#         [bug-project@example])
#

case $# in
    1) ;;
    *) echo 1>&2 "Usage: $0 \$srcdir/.tarball-version"; exit 1;;
esac

tarball_version_file="$1"
nl='
'

# First see if there is a tarball-only version file.
if test -f $tarball_version_file
then
    v=`cat $tarball_version_file` || exit 1
    case $v in
	*$nl*) v= ;; # reject multi-line output
    esac
    test -z "$v" \
	&& echo "$0: WARNING: $tarball_version_file seems to be damaged" 1>&2

    printf '%s' $v
    exit
fi

cd "$(dirname "${tarball_version_file}")"

git_abbrev=
if git -h 2>&1 | grep -q -- '-c\>'; then
	git_abbrev="-c core.abbrev=12"
fi

# Check for git and a git repo.
if head=`git ${git_abbrev} rev-parse --verify --short HEAD 2>/dev/null`; then

	# If we are at a tagged commit (like "ptxdist-2010.05.0"), we
	# print it here
	if atag="`git describe --exact-match 2>/dev/null`"; then
		echo "$atag" | awk -F- '{printf("%s", $(NF))}'

	# If we are past a tagged commit (like "ptxdist-2010.03.0-130-g3c60777"),
	# we pretty print it.
	elif atag="`git ${git_abbrev} describe 2>/dev/null`"; then
		echo "$atag" | awk -F- '{printf("%s-%05d-%s", $(NF-2),$(NF-1),$(NF))}'

	# If we don't have a tag at all we print ????.??.?-?-g{commitish}.
	else
		printf '%s%s' '????.??.?-?-g' $head
	fi

	# Is this git on svn?
	if git config --get svn-remote.svn.url >/dev/null; then
	        printf -- '-svn%s' "`git svn find-rev $head`"
	fi

	# Update index only on r/w media
	[ -w . ] && git update-index --refresh --unmerged > /dev/null

	# Check for uncommitted changes
	if git diff-index --name-only HEAD \
	    | read dummy; then
		printf '%s' -dirty
	fi

	# All done with git
	exit
fi

# Check for mercurial and a mercurial repo.
if hgid=`hg id 2>/dev/null`; then
	tag=`printf '%s' "$hgid" | cut -d' ' -f2`

	# Do we have an untagged version?
	if [ -z "$tag" -o "$tag" = tip ]; then
		id=`printf '%s' "$hgid" | sed 's/[+ ].*//'`
		printf '%s%s' hg "$id"
	fi

	# Are there uncommitted changes?
	# These are represented by + after the changeset id.
	case "$hgid" in
		*+|*+\ *) printf '%s' -dirty ;;
	esac

	# All done with mercurial
	exit
fi

# Check for svn and a svn repo.
if rev=`svn info 2>/dev/null | grep '^Last Changed Rev'`; then
	rev=`echo $rev | awk '{print $NF}'`
	printf -- 'svn%s' "$rev"

	# All done with svn
	exit
fi
